Pressure-actuated drum dispenser

ABSTRACT

A pressure-actuated drum dispenser which is mountable to an opening in the top of a drum. The dispenser includes a tubular housing with an upright wall and which is mountable at its lower end to the drum opening. The housing has an air entrance valve normally spring biased in a closed position in its wall. An upright discharge pipe extends through the housing and is sealed to the upper end of the housing. The pipe is spaced inwardly of the housing wall to provide an annular space between the housing and the pipe, the annular space extending downwardly for communication with the drum interior. Angled upwardly and outwardly from the housing wall is a vent tube which communicates with the annular space and which terminates upwardly in a wide mouth permitting material to be added to the drum. Releasably attached to the mouth is a pressure relief valve which includes a cap mountable to the mouth and having a spring-loaded plug extending inwardly of the mouth for seating against an annular valve seat within the vent tube. An attachment for attaching the cap to the mouth has three positions, one position seating the plug against the valve seat to seal the vent tube and also sealing the cap against the mouth, a second position wherein the plug is disengaged from the valve seat but the cap is retained on the mouth, and a third position permitting the cap and plug to be removed as a unit from the mouth of the vent tube.

llited Sites atet 1 Moos [ 1 Dec.3,1974

[ 1 PRESSURE-ACTUATED DRUM DISPENSER [75] Inventor: Ervin A. Moos, Minneapolis, Minn.

[73] Assignee: Thexton Manufacturing Company,

St. Louis Park, Minn.

22 Filed: Nov. 19,1973

21 Appl. No.: 417,474

Primary Examiner-Stanley H. Tollberg Assistant ExaminerJohn P. Shannon Attorney, Agent, or Firm-H. Dale Palmatier; James R. Haller [57] ABSTRACT A pressure-actuated drum dispenser which is mountright discharge pipe extends through the housing and is sealed to the upper end of the housing. The pipe is spaced inwardly of the housing wall to provide an annular space between the housing and the pipe, the annular space extending downwardly for communication with the drum interior. Angled upwardly and outwardly from the housing wall is a vent tube which communicates with the annular space and which terminates upwardly in a wide mouth permitting material to be added to the drum, Releasably attached to the mouth is a pressure relief valve which includes a cap mountable to the mouth and having a spring-loaded plug extending inwardly of the mouth for seating against an annular valve seat within the vent tube. An attachment for attaching the cap to the mouth has three positions, one position seating the plug against the valve seat to seal the vent tube and also sealing the cap against the mouth, a second position wherein the plug is disengaged from the valve seat but the cap is retained on the mouth, and a third position permitting the cap and plug to be removed as a unit from the mouth of the vent tube.

10 Claims, 5 Drawing Figures PRESSURE-ACTUATED DRUM DISPENSER BACKGROUND OF THE INVENTION Oil, antifreeze and the like are normally shipped in bulk in large storage drums which may hold, for example 55 gallons of liquid. To remove liquid from such drums, it has heretofor been necessary to either tip the drums on their sides to pour the liquid therefrom, or to make use of volumetric pumps which have required the cranking of a handle or the like to dispense liquid from such drums. To avoid the mess, waste of time and the awkwardness heretofor associated with the removal of limited quantities of liquid from a drum, an easily mounted, inexpensive device permitting the withdrawal of limited quantities of liquid from a drum easily, quickly, and without mess or wastage of liquid is much to be desired.

BRIEF SUMMARY OF THE INVENTION Briefly, the present invention relates to a pressureactuated drum dispenser which is mountable to an'opening in the top of a drum. The drum dispenser comprises an upright tubular housing mountable at its lower end to the drum opening and having an air entrance valve, normally spring biased in a closed position, in its wall. An upright discharge pipe extends through the housing and is sealed to the upper end of the housing,'the pipe being spaced inwardly of the housing wall to provide an annular space between the housing and the pipe, the annular space extending downwardly for communication with a drum interior when the drum dispenser is mounted to a drum. A vent and access tube, angled upwardly and outwardly from the housing wall at an oblique angle to the housing axis communicates with the annular space between the housing and the discharge pipe. The vent tube has a wide, exteriorly accessible mouth, a valve seat spaced inwardly of the mouth, an air exit port between the mouth and the valve seat, and a pressure relief valve. The latter valve includes a cap releasably sealed to the mouth and having an inwardly directed plug spring-biased against the valve seat. The cap is attached to the mouth by an attachment having a closed position wherein the plug is spring-biased against the valve seat and the cap is sealed against the mouth, an open position permitting the cap and plug to be lifted from the mouth as a unit, and a position intermediate the open and closed positions wherein the plug is disengaged from the seat but the cap is retained on the mouth. The latter position permits air under pressure from the drum to be released between the plug and the valve seat and to exit through the port. When air under pressure has been introduced to the drum through the air entrance valve in the housing, any excess air pressure biases the plug from its seating engagement with the valve seat, permitting air to escape through the air exit port until the desired pressure within the drum has been obtained, the plug thereafter seating against the valve seat to maintain the desired pressure in the drum.

DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view of a drum dispenser of the invention mounted to the top of a drum, the latter being partially broken away;

FIG. 2 is an elevational view of the drum dispenser of FIG. 1, shown broken away and in partial cross section;

FIG. 3 is a broken away side view of the end ofa vent tube shown also in FIG. 2;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1; and

FIG. 5 is a plan view of a cap and plug mountable to the mouthof the vent tube of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the drum dispenser 10 of the invention includes an upright discharge pipe 12 having a horizontal bend at its upper end and terminating in a faucet 12.1 having an operating handle 12.2, the faucet normally being biased against spring pressure in a closed position. The discharge pipe extends downwardly through a housing designated generally as 14 and extends from the lower end of the housing into a drum 16 containing a liquid such as motor oil or antifreeze, the bottom end 12.3 of the discharge pipe extending below the surface of the liquid and resting against the floor 16.1 of the drum (FIG. 2). The bottom end 12.3 of the discharge pipe is normally cut at an angle, as shown in FIG. 2, or is otherwise slotted or perforated so that the pipe may rest upon the floor of the drum and still be provided with an opening 12.4 through which liquid from the drum may enter the pipe for eventual discharge through the faucet 12.1.

The upright housing 14 has an upright wall 14.1 which is circular in cross section and which encompasses the upright discharge pipe 12 throughout a portion of the length of the pipe adjacent the upper surface of the drum 16, the pipe being spaced inwardly of the housing wall to provide an annular space 17 therebetween which extends downwardly into communication with a drum upon which the housing is mounted. At its lower end, the wall 14.1 has a section 14.2 of increased diameter into which is telescopically received a lower sleeve 14.3 having an exteriorly threaded lower end. The threaded lower end of the sleeve is threadingly received in a bushing 16.1 which is threaded internally and externally, the external threads of which may be pipe threads fitting the threaded internal periphery of a hole designated generally as 16.2 in the lid 16.3 of the vdrum 16. As will be noted from FIG. 2, the lid 16.3 is

somewhat thickened by bending or the like at the point of the threaded hole 16.2 for rigid mounting of the bushing. If desired, the pipe threads of the bushing and the inner periphery of the hole 16.2 may be replaced with straight threads, and a gasket 16.4 of rubber or other resilient material may be placed between the upper surface of the hole and the lower surface of the bushing 16.1, the latter being formed by outwardly extending shoulders of the bushing which ordinarily terminate outwardly in a hexagonal configuration to permit gripping with a wrench, the gasket 16.4 being squeezed between the confronting surfaces of the hole and bushing. The interior of the bushing 16.1 may be provided with pipe threads fitting the lower threaded end of the sleeve 14.3, or straight threads may be used if desired. At least one pair of machine threaded surfaces between the sleeve 14.3 and the bushing 16.1 or between the latter and the drum opening 16.2 is desired so that the housing may be oriented as desired by rotation about its upright axis.

The wall 14.1 of the housing also has at its upper end a section of increased diameter 14.4, within which a sleeve 14.5 is adhered by solvent welding or the like.

The sleeve 14.5 has an internal diameter slidingly receiving the upright discharge pipe 12 and terminates upwardly in an edge 14.6 which tapers downwardly and inwardly toward the pipe 12. Carried upon the tapered edge 14.6 of the sleeve 14.5 is an O-ring 14.7 passing snugly about the periphery of the pipe 12. A bushing 14.8 fits slidably about the pipe 12 and has walls inter nally threaded to receive threads formed externally intermediate the length of the bushing 14.5. The bushing 14.8 has a lower internal surface 14.9 which bears downwardly upon the O-ring 14.7 so that the latter is urged downwardly against the tapered end 14.6 of the bushing and inwardly in sealing engagement against the pipe 12. As will be noted from FIG. 2, the sealing pressure of the O-ring against the pipe increases or decreases as the bushing 14.8 is screwed downwardly on or upwardly from the sleeve 14.5. When the bushing has been loosened on the sleeve 14.5, the pipe may turn within the bushing and sleeve so that the faucet 12.1 at the top of the pipe may be oriented in outwardly direction away from the barrel or in any desired direction.

Intermediate its length, the wall 14.1 of the housing is provided with an upwardly oriented vent and access tube 18 of circular cross section, the wall 18.1 of the vent tube merging with the wall 14.1 of the housing to communicate the interior of the vent tube with the annular space 17 between the wall 14.1 of the housing and the pipe 12. At its upper end the wall of the vent tube is provided with a section 18.2 of increased diameter within which may be solvent welded the smoothwalled end of a sleeve 18.3, the sleeve having a threaded, protruding end 18.4. About the end 18.4 of the sleeve 18.3 is threaded another sleeve 18.5 which may be of metal, and to the inner, upper periphery of the latter sleeve is welded a thin-walled meta! tube 20, the lower open end of which is bent inwardly to form an annular valve seat 20.1, and the outer end of which is bent outwardly to form a mouth 20.2 with an annular flange 20.3 extending outwardly and downwardly in a stepped fashion as shown most clearly in FIG. 3A. The wall of the tube 20 has an air exit port 20.4 communicating with the atmosphere and positioned between the valve seat 20.1 and the mouth, or rim, 20.2, the port 20.4 being provided with an outwardly directed spout 20.5 to which may be attached an air flow indicator proving an audible or visible indication of air flowv A pressure relief valve designated generally as 24 is provided with a cap 24.1 having an internal peripheral surface seating upon the mouth, or rim, 20.2 of the tube 20, the cap 24.1 having downwardly extending walls 24.2 terminating downwardly in inwardly extending ears 24.3. The ears are oriented to encounter and ride upon the lower, stepped surface of the downwardly oriented flange 20.3 of the tube 20. A plug 24.4 mounted at the bottom of telescoping tubes designated generally as 24.5, which in turn are mounted centrally of the cap 24, projects inwardly of the mouth for sealing against the valve seat 20.1, and is spring-biased inwardly by compression spring 24.6. The spring constant of the compression spring is selected so that the plug 24.4 is urged upwardly out of contact with the valve seat when the pressure within the housing and vent tube exceeds a predetermined level, such as 4 p.s.i.g. The ears 24.3 of the cap 24 and the steps 20.6, 20.7, 20.8 of the downwardly extending flange 20.3 coact to provide an attachment between the cap 24.1

and the tube 20. When the cap is in a first position with respect to the sleeve 20, the cap ears 24.3 are captured beneath the downwardly extending step 20.6 of the flange 20.3, the plug 24.4 being seated against spring pressure firmly in the valve seat 20.1 and the inner periphery ofthe cap seating firmly against the mouth 20.2 of the tube 20. As the cap is rotated with respect to the vent tube, the ears 24.3 slide from step 20.6 to the adjacent step 20.7, the latter step being spaced nearer the mouth 20.2. ln this position. the plug 20.4 disengages outwardly from the valve seat 20.1, and permits air under pressure from within the drum to pass through the annular space 17 and through the vent tube 18 to escape through the air exit port 20.4, but the cap is prevented from flying off under the pressure of air issuing through the vent tube by the cap ears 24.3 which are captured beneath step 20.7 of the tube 20. Continued rotation of the cap 24 causes the ears 24.3 to abut the edge of the step 20.8 and to escape into a recess in the flange 20.3, disengaging the ears from the flange and permitting the cap and plug to be lifted outwardly from the mouth 20.2.

Removal of the cap 24 from the mouth 20.2 permits material to be added to the drum through the mouth 20.2, the material passing through the wide opening de fined by the annular valve seat 20.1 and thence through the vent tube 18 and annular space 17 into the interior of the drum. The longitudinal axis of the upwardly and outwardly directed vent tube 18 is at an oblique angle to the axis of the housing 14, so that the mouth 20.2 opens upwardly to easily receive additive material and so that the material can pass by force of gravity through the vent tube and annular space into the drum. Desirably, the angle between the axes of the housing and the vent tube is 45 or less.

As noted above, an audible or visible air flow indica tor is attached to the spout 20.5 leading from the air exit port 20.4. Any of a number of indicators may be employed for this purpose, it being desired only that the indicator provide an audible or visible indication that air is escaping through the port 20.4. in the em bodiment depicted in the drawing, a flexible plastic balloon 26 having a transverse slit 26.1 is attached to the spout 20.5, and the air which passes through the spout and escapes through the slit in the balloon causes the balloon to wiggle back and forth, indicating to the op erator that the drum pressure is being relieved. In another embodiment, a whistle, or siren, may take the place of the plastic balloon 26 so that air issuing from the spout 20.5 will provide an audible whistle or wail, again indicating that drum pressure is being relieved.

The wall 14.1 of the housing is provided intermediate its ends with an air entrance valve 28 which may be cemerited into the wall 14.1 and which extends exteriorly of the wall as shown best in FIG. 4. The externally protruding end of the valve 28 is in the form of a nozzle having an end 28.1 configured to receive the end of an air pressure hose of the type normally used in automobile repair shops, and has internal valving 28.2 including a valve seat and plug, the internal valving including an exteriorly accessible valve stem which extends substantially to the outer end 28.1 of the valve. The valve stem is spring biased in a closed position to normally prevent air from either entering or exiting through the nozzle, the valve stem being centered within the nozzle so as to encounter the center projection of the end of an air pressure hose and to be urged inwardly to open the valve when pressure is applied through the nozzle to the drum. Upon removal of the air pressure hose, the valve stem returns to its original closed position and the valve remains closed. If desired, air under pressure from within the drum may be bled from the drum slowly by depressing the valve stem so as to open the valve 28. In one embodiment, an air pressure regulator 28.3 having a high pressure side and a low pressure side may be attached at its low pressure side to the nozzle 28 and an air pressure hose carrying airunder higher pressures than that desired within the drum may be attached to the high pressure side of the regulator, the regulator serving to permit air to enter the valve only when the internal pressure (drum pressure) is below a predetermined level. Air pressure regulators capable of receiving air under high pressure and delivering air at a lower, regulated pressure are known to the art and need not be described here. It will be noted that air under pressure which is conveyed inwardly through the valve 28 does not bear directly on the plug 24.4 of the pressure relief valve 24, and clear passage between the air entrance valve 28 and the pressure relief valve 24 is ordinarily blocked by the presence of the central discharge pipe 12 within the housing 14.

It will be understood, of course, that the device of the present invention is not intended for use with flammable solvents having low flash points such as gasoline and the like, but rather is intended for liquids which are substantially less flammable or non-inflammable such as motor oil, antifreeze (ethylene glycol type), aqueous windshield-washer solutions, and the like. Whenused with 55 gallon drums, or like drums ordinarily used to transport liquids, the pressure relief valve of the dispenser of my invention may be pre-set to release at a drum pressure of about 4 p.s.i.g., and the pressure of this magnitude ordinarily may be safely tolerated by such drums since drums of this type ordinarily are pressure tested at pressures of about twice this magnitude. A pressure of4 p.s.i.g. ordinarily does not cause a fiftyfive gallon drum to bulge noticably, but yet provides sufficient force to urge relatively non-viscous liquids through the pipe 12 for discharge through the faucet 12.1.

The drum dispenser of the invention may be varied in size to accommodate various sized drums and liquids of varying viscosities. The bushing 16.1 is of a size adapted to fit the upper drum opening which is common to most liquid-transporting drums, and the depth to which the discharge pipe 12 is inserted within the drum may be varied by loosening the bushing 14.8 at the top of the housing and sliding the pipe vertically through the housing until the end 12.3 of the pipe touches the floor of the drum, after which the bushing 14.8 may then be tightened to provide an air tight seal between the top of the housing and the pipe.

The seals which are provided between the bottom of the housing and the drum opening, the top of the housing and the pipe, and at the open end of the vent tube by the pressure relief valve, are air-tight so as to retain several pounds of pressure within the drum for extended periods of time. When the housing has been attached to the drum by means of the bushing 16.1, and the discharge pipe 12 has been adjusted vertically within the housing to extend to the bottom of the drum, the cap 24.1 is turned down tightly upon the mouth 20.2 of the vent tube so that the ears 24.3 are captured beneath the steps 20.6. Air is then introduced to the drum through the air entrance valve 28 until the pressure in the drum has reached its desired level, this level being signaled by an audible or a visible signal from the air flow indicator 26. The air pressure hose is then disconnected from the air entrance valve 28, and air continues to slowly escape through the air exit port 20.4 until the correct pressure within the drum has been attained. Due to the rather large area of contact between the valve seat 20.1 and the plug 20.4, the release of excess pressure from the drum is ordinarily accomplished quite rapidly, and the drum pressure is never allowed to exceed a safe limit. Liquid may then be withdrawn from the drum by simply opening the faucet 12.1 by

vmanual movement of the handle 12.2, the air under .drum, and frequent recharging of the drum with air under pressure may be necessary. On the other hand, when the drum has been largely depleted of liquid, at single charge of air under pressure to the drum will suffice to enable the remainder of the liquid to be discharged without further pressurizing of the drum. When equipped with an air pressure regulator as described above, air under pressure is made continuously available to the valve 28, but air passes inwardly through the valve only when the pressure within the drum has been depleted below a pre-set value such as 4 p.s.i.g. With the air pressure regulator attached, the valve stem .of the air entrance valve is continuously depressed, opening the valving and permitting the low pressure side of the air regulator to continuously communicate with air within the drum. In this embodiment, the pressure of air within the drum is regulated not only by the air regulator attached to the valve 28 but also by the pressure relief valve 24 at the end of the air vent tube 18, the air regulator permitting air under pressure to enter the drum only when the pressure in the drum has been decreased below certain limits, and the pressure relief valve functioning to release pressure within the drum should the air pressure regulator for any reason deliver excess air to the drum.

The walls 14.1 and 18.1 of the housing and vent tube, the sleeves 14.5, 14.3 and 18.3, the bushing 14.8 and the discharge pipe 12 may be all fashioned from rigid plastic materials such as polyvinylchloride, and the sleeve 18.5 and sleeve end 20 are desirably fashioned from metal such as brass or steel. The joints between mating, smooth-walled plastic parts (e.g., between the lower sleeve 14.3 and the bottom end 14.2 of the housing wall) may be joined by solvent or adhesive welds or the like. The pressure relief valve 24 is of metal save for the plug 24.4 which may be of rubber or other resilient material. If desired, the sleeves 14.5, 14.3 and 18.3 and the walls 14.1 and 18.1 of the housing and vent tube may be integrally molded, in split sections if desired, to reduce assembly time.

Manifestly, l have provided a pressure-actuated drum dispenser which is easily mounted to the lid'of a drum, which is safe, easy to operate, inexpensive to manufacture, and readily changable between drums of different sizes. The upwardly angled vent tube of my dispenser, equipped with a wide mouth and large diameter interior, permits material to be added through the mouth to the drum as desired without mess and without requiring the dispenser to be removed from the drum.

While I have described a preferred embodiment of the present invention, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.

Wnat is claimed is:

1. A pressure-actuated drum dispenser mountable to an opening in the top of a storage drum and comprising;

an upright tubular housing mountable at its lower end to the drum opening and having an air entrance valve intermediate its ends communicating with the housing interior;

an upright discharge pipe extending through the housing and sealed to the upper end of the housing, the pipe being spaced inwardly of the housing to provide an annular space between the housing and the pipe which opens downwardly for communication with the interior of a drum; vent and access tube angled upwardly and outwardly at an oblique angle from the housing intermediate the housing ends and communicating with the annular space, the vent tube having a wide, exteriorly accessible mouth, a valve seat on the tube and spaced inwardly of the mouth, an air exit port between the mouth and the valve seat; and

a pressure relief valve pre-set to open under a preselected pressure and including a cap having a springbiased plug seatable against the valve seat and a cap attachment releasably attaching the cap to the mouth, the attachment having a closed position seating the plug under spring pressure against the valve seat and sealing the cap to the mouth, an open position permitting the cap and plug to be lifted from the mouth as a unit, and a position intermediate the open and closed positions wherein the plug is disengaged from the seat but the cap is retained on the mouth, the latter position permitting air under pressure to be safely bled from the drum through the air exit port while safely maintaining the cap on the mouth of the vent tube.

2. The drum dispenser-of claim 1 wherein the air exit port includes an air flow indicator providing a signal in response to the passage of air through the port to indicate that drum pressure is being relived.

3. The drum dispenser of claim 2 wherein the signal provided by the air flow indicator is audible.

4. The drum dispenser of claim 2 wherein the signal provided by the air flow indicator is visible.

5. The drum dispenser of claim 1 wherein the air entrance valve includes an exterior nozzle connectable to an air line and including exteriorly operable, springloaded valving for opening and closing the valve, the valve permitting the flow of air through it in either direction when the valve is open, but preventing the outward flow of air when the valve is closed.

6. The drum dispenser of claim 5 wherein the air entrance valve includes an air pressure regulator having high pressure and low pressure sides, the low pressure side communicating through the air entrance valve with the interior of the housing and the high pressure side being connectable to a source of air under pressure higher than thepreselected pressure in the drum.

7. The drum dispenser of claim 1 wherein the upright discharge pipe terminates upwardly in a faucet having a manually operable valve normally spring'biased in a closed position and wherein the pipe terminates downwardly in an end contactabie with the bottom ofa drum and has an opening spaced upwardly from its terminal end through which liquid may enter the pipe.

8. The drum dispenser of claim 6 wherein the upper end of the housing slidably engages the pipe about its periphery and terminates upwardly in an O-ring seat and wherein the dispenser includes an O-ring seated in the O-ring seat and an O-ring sleeve slidably 6l'lCOl'11 passing the discharge tube and threaded to the upper end of the housing and having a lower surface bearing downwardly against the O'ring, whereby the upper end of the housing and the bearing surface of the O-ring sleeve cooperate to force the O-ring inwardly into sealing engagement with the discharge tube.

9. The drum dispenser of claim 8 wherein the housing contacts the discharge pipe solely at the upper end of the former, whereby, upon loosening the O-ring sleeve, the discharge pipe may be easiy raised. lowered, or ro tated about its axis.

10. A pressure-operated drum dispenser mountable to a threaded hole in the top of a storage drum and comprising:

an upright discharge pipe for conveying liquid from the drum and having a lower receiving end insertable into liquid within the drum and an upper end having a faucet spring-biased in a closed position for discharge of liquid from the drum;

an upright, tubular housing for connecting the pipe to the drum and housing the pipe intermediate the pipe ends, the housing having a lower end sealably connectable to the threaded opening in the drum and having an upper end sealably connected to the pipe, the housing having a peripheral wall spaced from the pipe and defining an annular space between the pipe and housing. the space extending downwardly for communication with the drum interior, the housing having intermediate its ends an air entrance port with a valve therein. the valve having exteriorly operable valving and a nozzle for connection to an air pressure hose, the air entrance valve being spring-biased in a normally closed position preventing outward flow of air;

a vent and access tube arising at an acute angle from the housing wall and communicating with the annular space, the vent tube having a wide, upwardly oriented and exteriorly accessible mouth enabling material to be added to the liquid in the drum through the mouth, the vent tube having an annular valve seat spaced internally of the mouth, an air exit port spaced between the valve seat and the mouth and communicating with the atmosphere. an air flow indicator at the port to indicate escape of air therethrough, having a cap attachable to the outer periphery of the mouth and an inwardly extending, spring-loaded plug seatable against the valve seat and openable outwardly against pre-set spring pressure, the cap having an outer periphery with downwardly and inwardly bent ears cooperating with ear seats at the exterior periphery of the mouth. the ear seats providing a first cap position wherein the ears of the cap are biased downwardly to seal the cap against the mouth and to seat the plug against the valve seat, a second cap position achieved by rotating the cap with respect to the mouth through a predetermined angle and in which the plug is spaced from the valve seat but the ears are yet confined by the ear seats, and a third cap position achieved by depression and further rota tion of the cap wherein the ears are freed from the ear seats and the cap and plug are removable outwardly as a unit from the mouth. 

1. A pressure-actuated drum dispenser mountable to an opening in the top of a storage drum and comprising; an upright tubular housing mountable at its lower end to the drum opening and having an air entrance valve intermediate its ends communicating with the housing interior; an upright discharge pipe extending through the housing and sealed to the upper end of the housing, the pipe being spaced inwardly of the housing to provide an annular space between the housing and the pipe which opens downwardly for communication with the interior of a drum; a vent and access tube angled upwardly and outwardly at an oblique angle from the housing intermediate the housing ends and communicating with the annular space, the vent tube having a wide, exteriorly accessible mouth, a valve seaT on the tube and spaced inwardly of the mouth, an air exit port between the mouth and the valve seat; and a pressure relief valve pre-set to open under a preselected pressure and including a cap having a spring-biased plug seatable against the valve seat and a cap attachment releasably attaching the cap to the mouth, the attachment having a closed position seating the plug under spring pressure against the valve seat and sealing the cap to the mouth, an open position permitting the cap and plug to be lifted from the mouth as a unit, and a position intermediate the open and closed positions wherein the plug is disengaged from the seat but the cap is retained on the mouth, the latter position permitting air under pressure to be safely bled from the drum through the air exit port while safely maintaining the cap on the mouth of the vent tube.
 2. The drum dispenser of claim 1 wherein the air exit port includes an air flow indicator providing a signal in response to the passage of air through the port to indicate that drum pressure is being relived.
 3. The drum dispenser of claim 2 wherein the signal provided by the air flow indicator is audible.
 4. The drum dispenser of claim 2 wherein the signal provided by the air flow indicator is visible.
 5. The drum dispenser of claim 1 wherein the air entrance valve includes an exterior nozzle connectable to an air line and including exteriorly operable, spring-loaded valving for opening and closing the valve, the valve permitting the flow of air through it in either direction when the valve is open, but preventing the outward flow of air when the valve is closed.
 6. The drum dispenser of claim 5 wherein the air entrance valve includes an air pressure regulator having high pressure and low pressure sides, the low pressure side communicating through the air entrance valve with the interior of the housing and the high pressure side being connectable to a source of air under pressure higher than the preselected pressure in the drum.
 7. The drum dispenser of claim 1 wherein the upright discharge pipe terminates upwardly in a faucet having a manually operable valve normally spring-biased in a closed position and wherein the pipe terminates downwardly in an end contactable with the bottom of a drum and has an opening spaced upwardly from its terminal end through which liquid may enter the pipe.
 8. The drum dispenser of claim 6 wherein the upper end of the housing slidably engages the pipe about its periphery and terminates upwardly in an O-ring seat and wherein the dispenser includes an O-ring seated in the O-ring seat and an O-ring sleeve slidably encompassing the discharge tube and threaded to the upper end of the housing and having a lower surface bearing downwardly against the O-ring, whereby the upper end of the housing and the bearing surface of the O-ring sleeve cooperate to force the O-ring inwardly into sealing engagement with the discharge tube.
 9. The drum dispenser of claim 8 wherein the housing contacts the discharge pipe solely at the upper end of the former, whereby, upon loosening the O-ring sleeve, the discharge pipe may be easiy raised, lowered, or rotated about its axis.
 10. A pressure-operated drum dispenser mountable to a threaded hole in the top of a storage drum and comprising: an upright discharge pipe for conveying liquid from the drum and having a lower receiving end insertable into liquid within the drum and an upper end having a faucet spring-biased in a closed position for discharge of liquid from the drum; an upright, tubular housing for connecting the pipe to the drum and housing the pipe intermediate the pipe ends, the housing having a lower end sealably connectable to the threaded opening in the drum and having an upper end sealably connected to the pipe, the housing having a peripheral wall spaced from the pipe and defining an annular space between the pipe and housing, the space extending downwardly for communication with the drum interior, the housing Having intermediate its ends an air entrance port with a valve therein, the valve having exteriorly operable valving and a nozzle for connection to an air pressure hose, the air entrance valve being spring-biased in a normally closed position preventing outward flow of air; a vent and access tube arising at an acute angle from the housing wall and communicating with the annular space, the vent tube having a wide, upwardly oriented and exteriorly accessible mouth enabling material to be added to the liquid in the drum through the mouth, the vent tube having an annular valve seat spaced internally of the mouth, an air exit port spaced between the valve seat and the mouth and communicating with the atmosphere, an air flow indicator at the port to indicate escape of air therethrough, having a cap attachable to the outer periphery of the mouth and an inwardly extending, spring-loaded plug seatable against the valve seat and openable outwardly against pre-set spring pressure, the cap having an outer periphery with downwardly and inwardly bent ears cooperating with ear seats at the exterior periphery of the mouth, the ear seats providing a first cap position wherein the ears of the cap are biased downwardly to seal the cap against the mouth and to seat the plug against the valve seat, a second cap position achieved by rotating the cap with respect to the mouth through a predetermined angle and in which the plug is spaced from the valve seat but the ears are yet confined by the ear seats, and a third cap position achieved by depression and further rotation of the cap wherein the ears are freed from the ear seats and the cap and plug are removable outwardly as a unit from the mouth. 